Alloy and dental article



INVENTOR OVA/E2 1)" 0/577 )BY 7 ATTO NEY C DIETZ ALLOY AND DENTAL ARTICLE Filed NOV. 24, 1241 Patented Feb. 9,1943

mow AND DENTAL .mrrcm Charles Dietz, York, Pa., assignor to The Dentists Supply Company of New York, New York, N. Y., a corporation of New York Application November 24, 1941, Serial No. 420,227 9 Claims. (Cl. 75-172) The invention relates to metal alloys and dental articles made of, or containing, such alloys. More particularly, it relates to improvements in palladium alloys containing platinum or gold, or platinum and gold.

Alloys of palladium and platinum; palladium and gold; and palladium, platinum and gold are useful for various purposes, such as for articles employed in dentistry, for example the pins and anchorages or other securing means for artificial teeth. Alloys of these metals, containing a preponderance of palladium. are useful particularly as substitutes for platinum alloys, and are much less expensive, not only because of the lower cost of palladium per unit weight, but also because of the lower specific gravity of palladium which gives a very decided advantage to palladium over both platinum and gold from the standpoint of cost per unit volume. These alloys have a relatively high melting point, but when subjected to temperatures on the order of 2400" Fahrenheit, the surface will turn a bluish color, apparently because of thehigh content of palladium. It is an object of my invention to provide high palladium alloys which are not subject to this disadvantage, and which have other improved characteristics, making them useful for many purposes.'

Another object of my invention is to provide alloys of the character described which have properties making them particularly "useful to the manufacturing dentist for purposes such as in making pins and anchorages or other securing means for artificial teeth.

A further object of my invention is to provide dental articles such as 'pins and anchorages which are inexpensive as compared-with such articles when made with platinum alloys, yet which can be subjected to temperatures normally employed in fusing porcelain teeth with-, out discoloration of the metal surfaces. and which possess improved soldering characteristics.

A further object is to provide an improved fused porcelain tooth having anchorages of a high palladium alloy, said tooth being characterized by improved adhesion between the porcelain and metal as compared with teeth having anchorages of platinum, palladium or gold, or alloys of these metals heretofore known.

Other objects and advantages of the invention will appear as the description proceeds.

While my improved alloy is particularly useful for any purpose requiring high palladium metals which can be subjected to high tempertal articles, and more specifically with reference to pins and anchorages for artificial teeth. In-

sofar as concerns the improved alloy per se, the

invention is not limited to these articles, and no such limitation is implied.

In the manufacture of artificial teeth having pins for anchoring the teeth in place in the dentures, as used quite generally in the case of anteriors, a common practice is to imbed a metal anchorage member in the tooth material during the moulding of the tooth. Thereafter the tooth is baked, or fired to fuse the porcelain. and upon completion of the firing step the pins are soldered to the imbedded anchorages. Some palladium alloys, used as substitutes for platinum alloys, are relatively inexpensive, and possess characteristics which make them suitable for use in anchorages, but oxidize when heated to the fusing temperatures of the porcelain used in teeth. This is particularly true of alloys containing higher contents of palladium, for example, those containing 60 per cent or more of palladium, which when heated to, say, 2400 Fahrenheit will turn a bluish color.

I have found that the addition of from about 2 per cent to about 15 per cent of silver to alloys comprising from about 60 per cent to about per cent of palladium and from about 10 per cent to about 35 per cent of platinum is very effective in preventing or minimizing the formation of the blue oxide on the surface of articles made therefrom when heated to temperatures on the order of 2400 Fahrenheit. I have also found that the resulting alloys possess other valuable properties, as will be described.

As specific examples of my improved alloy, I disclose below a number of compositions which I have tested and found to be effective for the purposes of the invention:

It will ofcourse be understood that various other which is an important advantage because these parts are very delicate and have thin walls which otherwise would be likely to collapse under pressure. 7

I have found, further, that if the silver content does not substantially exceed about 15 per cent of the alloy, the alloy will not only possess the desirable characteristics I have described, but will be substantially free from the surface blisters which occur with alloys containing greater amounts of silver when heated to tooth burning temperatures. When alloys containing silver in amounts substantially greater than 15 per cent are subjected to temperatures such 2400 Fahrenheit, the silver has a tendency to sweat out of the alloy, producing a blistered and unattractive appearance. Furthermore, larger amounts of silver lower the melting point without conferring substantial additional benefits insofar as concerns the stated objects of my invention. Optimum properties are obtained within the percentage llmits stated.

Gold may be substituted for some or all of the platinum when the relative prices of these two metals indicate that this would be economical.

Alloy F: Per cent Palladium 65 Gold 25 Silver 10 Alloy G: Per cent Palladium '15 Gold Silver 10 Again itmust be understood that these examples are disclosed merely as representative alloys falling within the stated composition ranges. Within these ranges, the percentages may be varied to produce an infinite number of compositions each possessing in substantial degree the desirable properties of my invention.

While I have described my alloy with emphasis on its essential constituents. namely, palladium and silver with either one or both of the elements platinum and gold, it is not my intention to exclude other additions which may be desired for usual purposes such as increasing hardness, or modifying other physical properties in manners known to the art. Relatively unimportant amounts of such additional elements as may be present without substantially altering the advantages 'of my invention as to heat resistance, pronounced porcelain-to-metal adhesion and other described properties, may be included without departing from the spirit of my invention, and I contemplate the presence of such constituents as modifiers for known purposes, or as impurities.

Further advantages of my invention are realized when dental anchorages of the disclosed alloy are combined with a porcelain tooth in such a manner as to form a permanent part thereof. I have discovered that when porcelain is fused against a dental article composed of this alloy, the porcelain has a marked tendency to adhere to the metal surface, whereas in the case of alloys containing only palladium and platinum, or palladium and gold, or palladium, platinum and gold, there is little adhesion between the metal and the porcelain. Thus, when an anchorage made of my alloy is imbedded in the tooth material during the moulding of the tooth, as I have described, and the tooth then is fired to fuse the porcelain, there is provided an improved fused porcelain tooth characterized by improved adhesion between the porcelain and metal as compared with teeth having anchorages of platinum, palladium or gold, or alloys of these metals heretofore known. In order that this aspect of my invention will be fully understood, reference now is made to the accompanying drawing illustrating one form of tooth embodying my invention.

Fig. 1 is a back view of a tooth having porcelain material fused against anchorages composed of the alloy I have disclosed, and having pins soldered to the anchorages. Fig. 2 is a vertical sectional view taken on th line 2-2 of Fig. 1; and Fig. 3 is a horizontal sectional view taken on the line 3-3 of Fig. 1.

Figs. 4 and 5 are perspective views of dental fastening elements such as employed in the tooth of Figs. 1 to 3, Fig. 4 showing an anchora e memher, and Fig. 5 a pin.

While my invention is applicable to many different forms of teeth, and to various types of fastening elements, I have selected for purposes of illustration a typical anterior tooth having what is known as the pin type of fastening. An anchorage member III of suitable form is moulded in situ in a porcelain enamel tooth l I in accordance with any well-known moulding method. The anchorage l0 may, if desired, beprovided with a securing flange l2, although the present invention is not concerned with the form of the anchorage which may be of any conventional type. In the embodiment shown, two of these anchorages provided, as shown best in Fig. 3. At the conclusion of the moulding operation, the tooth is baked, or fired, to fuse the porcelain at a temperature which may run on the order of 2400 Fahrenheit. The resulting tooth is characterized by improved adhesion between the porcelain and metal as compared with teeth having anchorages made of alloys heretofore known for this purpose.

After the tooth has been fired, pins l3 are soldered to the anchorage members Ill. Anchorage members of .the form illustrated provide a sleeve with central apertures M to receive the ends of the plus. The solder may coat the adjacent surfaces of the fastening elements l0 and I3, and may occupy the space at the base of the aperture M, as at l5, as well as part of the space l6 between the pins l3 and the porcelain, as at H. A more perfect solder union is obtained when the alloy I have disclosed'is employed for the anchorages. This advantage I attribute to the fact that this alloy is less subject to surface discoloration or oxidation at the firing .tem-

peratures of the teeth. However, I do not wish for the improvement in this respect, or by any theoretical considerations whatsoever. Also, the

terms and expressions which I have employed are used in a descriptive and not a limiting sense, and I have no intention of excluding such equivalents of the invention described; or of portions thereof, as fall within the purview of the claims.

The expression non-tarnishing precious metal(s) as used in the specification and in the accompanying claims refers to the 'metals gold and/or platinum.

I claim:

1. An alloy comprising metal from the group consisting of 60 to 85 parts of palladium with to 85 parts of palladium with to 35 parts of palladium with 10 to 35 parts of gold, and 60 to 85 parts of palladium with 10 to 35 parts of platinum and gold, alloyed with from 2 to 10 parts of silver, said alloy being characterized by high resistance to discoloration and excessive blistering at high temperatures.

2. An alloy comprising from about 60 to 85 per cent of palladium, from about 10 to 35 per cent of platinum, and from about 2 to 10 per cent of silver, said alloy being characterized by high resistance to discoloration and excessive blistering at high temperatures.

3. An alloy comprising from about 60 to 85 percent of palladium, from about 10 to 35 per cent of gold, and from about 2 to per cent of silver, said alloy being characterized by high resistance to discoloration and excessive blistering at high temperatures. I

4. An alloy consisting of about 70 per cent of palladium, about per cent of platinum, and about 5 per cent of silver.

5. A dental fastening element in the form of a shaped member composed of an alloy comprising metal from the group consisting oi. 60 to 85 parts of palladium with 10 to 35 parts of platinum, to 85 parts of palladium with 10 to 35 parts of gold, and 60 to 85 parts of palladium with 10 to 35 parts of platinum and gold, alloyed with from 2 to 15 parts of silver.

6. A dental anchorage member for making a soldered connection to a pin and the like, said member being made from an alloy comprising metal from the group consisting of 60 to'85 parts of palladium with 10 to 35 parts of platinum,

60 to 85 parts of palladium with 10 to 35 parts of gold, and 60 to 85 parts of palladium with 10 to 35 parts of platinum and gold, alloyed with from 2 .to 15 parts of silver.

7. In combination, a dental fastening element composed of an alloy comprising metal from the group consisting of 60 to 85 parts of palladium with 10 to 35 parts of platinum, 60 to 85 parts of palladium with 10 to 35 parts of gold, and 60 to 85 parts of palladium with 10 to 35 parts of platinum and gold, alloyed with from 2 to 15 parts of silver, and a porcelain tooth, said porcelain being fused against said fastening element.

8. In combination, a dental fastening element composed of an alloy comprising metal from the group consisting of 60 to 85 parts of palladium with 10 to 35 parts of platinum, 60 to 85 parts of palladium with 10 to 35 parts of gold, and 60 to 85 parts of palladium with 10 to 35 parts of platinum and gold, alloyed with from 2 to 15 parts of silver, and a porcelain tooth, said porcelain being fused against said fastening element, and a pin soldered to said fastening element.

9. A porcelain tooth fused'to a fastening element consisting of about per cent of palladium, about 25 per cent of platinum and about 5 per cent of silver.

CHARLES DIETZ.

CERTIFICATE OF CORRECTION. Patent No. 2,510,752. February 9, l9h5.

I CHARLES DIETZ.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, first column, line 21, after the word "such" insert -s.s-; and second column, lin 51, after"'anchorages" insert --ere-- page 5, first column, line 16, strike out "to 85 parts of palladium with 10 to'55 parts of" and insert instead --l0 to 55 parts of nlatinum, 60 to 85 parts ofand that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 6th day of April, A. D. 1911.5.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents. 

